The reinforcement of non-stick culinary item surfaces is a constant concern as it serves as a measure of durability.
Conventionally, sintered fluorocarbon resin-based coatings (for example PTFE) are applied to one or more surfaces of a culinary item as a means of forming a non-stick coating. Such coatings are known not only for their non-stick properties but also for their resistance to chemical and thermal damage.
Generally, culinary items, presenting a non-stick coating on their inner surface, have the advantage of being easily cleaned and make it possible to cook foods with little or no grease.
However, such items have a major disadvantage in that the non-stick coating is fragile.
The term fragile coating, in the context of the present invention, signifies a coating that is prone to scratching upon mechanical abrasion such as those caused by overly vigorous scouring pad scrubbing.
To address this major drawback and obtain a non-stick coating with improved mechanical properties, it is known to persons of ordinary skill in the art to produce a multi-layer non-stick coating, the first layer of which, from the support surface of the culinary item, (also known as the primer layer) serves as a surface onto which one or more additional layers of the non-stick coating (also known as finishing layers) contains, in addition to the sintered fluorocarbon resin, a high content of hard mineral or organic fillers (for example, silica, quartz or aluminum).
The addition of this type of fillers in coatings comprising at least one fluorocarbon resin makes it possible to improve resistance against abrasion, scratching and flaking (interlayer delamination).
However, this type of reinforcement is limited by the fact that the filler content in each coating layer cannot exceed more than a few percent by weight relative to the total weight of the layer. Beyond a certain threshold quantity of fillers, typically in excess of 15% by weight of fillers in the layer, the layer may not be able to adhere, particularly in the case of primer layers, or may lose its non-stick properties, particularly in the case of finishing layers.
Furthermore, it is known to persons of ordinary skill in the art to form a hard undercoat (also called a hard base) between the support (in this case the surface of a culinary item) and the non-stick coating (particularly the primer layer).
The establishment of a hard undercoat (or hard base) between the support and the non-stick coating makes it possible not only to improve the mechanical properties of the non-stick coating (particularly with respect to hardness), but also to ensure that the coating has a high scratch resistance.
The hard undercoat (or hard base) thus forms a barrier that prevents scratches from reaching the support.